1. Field
Embodiments disclosed herein relate to apparatuses and methods for manufacturing swellable packers. More specifically, embodiments disclosed herein relate to apparatuses and methods for manufacturing swellable packers having internal backup rings. More specifically still, embodiments disclosed herein relate to apparatuses and methods for manufacturing swellable packers having internal backup rings that reduce fracture propagation through swellable elastomers.
2. Background
This section introduces information from the art that may be related to or provide context for some aspects of the technique described herein and/or claimed below. This information is background facilitating a better understanding of that which is disclosed herein. This is a discussion of “related” art. That such art is “related” in no way implies that it is also “prior” art. The related art may or may not be prior art. The discussion is to be read in this light, and not as admissions of prior art.
In the oilfield industry, various downhole tools known as packers are used to isolate sections of a well. While various types of packers may be used, two commonly employed types of packers include mechanical/hydraulic setting, radially expandable packers and swellable packers. Mechanical/hydraulic setting radially expandable packers have a radially expandable elastomeric seal that is forced radially outward by either a mechanical or hydraulic force. The expanded elastomeric seal is typically held in place by a series of cones and lock rings that engage, thereby preventing the elastomeric seal from contracting. Certain hydraulic expandable packers activate under a flow of fluid, and stay expanded as long as the flow of fluid is maintained.
Swellable packers rely on elastomers that expand and form an annular seal when contacted with certain wellbore fluids. Typically, the elastomers used in swellable packers are either oil or water sensitive and the expansion rates and pressure ratings are affected by a number of factors, such as temperature, pressure, fluid content, etc. Oil activated elastomers are activated by contact with a hydrocarbon-based fluid, and the expansion is affected by fluid temperatures, as well as the concentration and specific gravity of the hydrocarbons in the fluid. Water activated elastomers are activated by contact with a water-based fluid. The expansion of water activated elastomers is affected by the water temperature and salinity.
During use, the elastomeric material of the swellable packers may be employed in harsh downhole environments that may include high temperatures, high pressures, and acidic or otherwise caustic environments. The downhole environment often results in cracks forming in one or more locations on the elastomeric material. When a crack forms, over time, the crack may propagate throughout the elastomeric material. As the crack grows, the sealing integrity of the swellable packer may degrade to the point where the swellable packer is no longer forming a barrier in the well, and the zones on either side of the packer are not separated. When such a condition occurs, the packer is said to have failed and requires removal and replacement.
Accordingly, there exists a continuing need for swellable packers that resist crack propagation. The presently disclosed technique is directed to resolving, or at least reducing, one or all of the problems mentioned above. Furthermore, the art is always receptive to improvements or alternative means, methods and configurations.